A Southeast Washington man convicted of second-degree murder in connection with a fiery 1981 automobile crash that took the life of an 11-year-old girl was sentenced yesterday to a minimum of 11 years in prison.

William A. Powell, whom District police testified they chased at speeds of 82 mph before his car crashed into another vehicle in which Melanie Nicholson and her father were riding to church, became the first driver in Washington since 1940 to be found guilty of murder with an automobile as the weapon.

Yesterday's sentence is the most severe levied for such a case in recent years in the Washington area and follows a national trend of stiffer punishments for drivers involved in fatal accidents.

In sentencing Powell, D.C. Superior Court Judge Joseph M. Ryan called it "a most unusual case" and cited what he called Powell's "cold-blooded disregard for other persons."

Before yesterday's hearing, Powell's defense attorney, Mark S. Carlin, told Ryan: "I'm almost speechless in this case. I've never seen a case like this and I hope I never see one like it again." The crash, he said, "was an accident" and Powell "just wishes that some day he could be forgiven."

Assistant U.S. Attorney Pamela B. Stuart asked for a "substantial" penalty against Powell, saying Powell's reckless use of his automobile "was just like he had cut someone with a knife and left them to die."

Clarence W. Nicholson, who was critically injured in the crash but managed to escape his flaming Honda after it was struck from behind by Powell's Cadillac, said of the sentence: "I guess it's fair. I just want Melanie back."

Nicholson's car, stopped at a traffic signal at Massachussetts Avenue and Second Street NW, was reduced to half its length in the 10:30 a.m. collision on Oct. 25, 1981. Melanie Nicholson was trapped inside and burned to death as her father and onlookers watched, helpless to free her.

On the morning of the accident, Powell, a custodian who was on probation for possession of heroin, was driving to a downtown methadone clinic where he had been undergoing treatment.

According to trial testimony, Powell was clocked by police at more than 80 mph in a 35-mph zone on Suitland Parkway. Police testified that they chased him onto the Southeast Freeway, through the Third Street tunnel and onto an exit ramp leading to the intersection where the crash occurred.

Carlin, who had called "preposterous" the prosecutors' theory that Powell had his foot on the accelerator at the time of the collision, yesterday asked for leniency, saying that the crash was "something Powell never foresaw would happen."

Powell, he said, is "haunted by this" and "wishes it was he that had died and not Melanie Nicholson."

Prosecutor Stuart, who argued at the trial that Powell's driving was so reckless it warranted a guilty verdict for murder, told Ryan that Powell "can't come to grips with his responsibilities for living in a civilized society."

She said Powell, who previously had been convicted of larceny and drug possession, "was and is a murderer in this case and still won't face up to it.

"Cars are just as dangerous as guns," Stuart added. "The only difference is that cars have a legitimate use and guns don't."

Judge Ryan said the absence of alcohol in the accident only increased Powell's culpability. He sentenced Powell to 11 to 33 years on the murder charge and 3 to 9 years for assault with a dangerous weapon, with the two sentences to run concurrently.

Powell could have been sentenced to life in prison.

In the past, prosecutors traditionally have filed lesser charges of manslaughter or negligent homicide in such cases. The last such conviction in the District of Columbia was in 1940 when a 26-year-old laborer from Missouri, Richard C. Nestlerode, was convicted of second-degree murder after his speeding car struck and killed two pedestrians.

Nestlerode was sentenced to 15 years to life.

In September, a drunken driver in Warrenton was convicted of second-degree murder in a crash that left three people dead. Warren Wesley Essex was sentenced to 15 years in prison, with 10 years suspended.